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Anatomy Lecture
Exam Three Chapter 20
| Blood Pressure | force per unit area that blood exerts against inside of wall vessel |
| Blood pressure gradient | change in blood from one end of a vessel to its other end |
| pressure is highest in | arteries |
| pressure is lowest in | veins because they are further away from the heart |
| Arterial blood pressure | Rhythmic pumping of blood through heart produces pulsing of blood through the arteries |
| Systolic pressure | occurs during ventricular systole (contraction), highest pressure generated in the arteries |
| Systole is | top number in ratio, contraction of the heart |
| Diastole is | Bottom number in the ratio, relaxation of the heart |
| Pulse pressure | Pressure in arteries added by heart contraction pulse pressure allows for palpation of throbbing pulse in elastic and muscular arteries |
| what is the formula for pulse pressure | pp = systolic number - diastolic number |
| what tends to happen to your arteries as you age | the elasticity and recoil declines |
| Pulse | throbbing of arterial wall More forceful pulse associated with higher pressure |
| What does an absence of pulse indicate | it indicates blood flow to a body part is lacking |
| What is blood pressure measure indirectly with | sphygmomanometer |
| Greater the vessel size means | the blood pressure will be slower |
| Pulse pressure is pulsatile until it reaches | the capillaries |
| Mean arterial pressure | average arterial blood pressure across entire cardiac cycle |
| since the heart spends more time in diastole what does that mean about the MAP | the mean will be weighted to be closer to diastolic pressure |
| formular for MAP | MAP = diastolic pressure + 1/3 pulse pressure |
| edema | trying to force out more blood or fluid than the body has so it pushes excess fluid to tissues |
| Venous return | movement of blood from capillaries back to heart via veins |
| skeletal muscle pump | Assists venous return from limbs |
| how does the skeletal muscle pump work | as muscle contracts, veins are squeezed Blood is pushed and valves prevent backflow Blood is moved more quicky during exercise Blood pools in leg veins with prolonged inactivity |
| Resistance | the friction blood encounters while being transported thriugh vessels (opposes blood flow) |
| Peripheral resistance | Resistance of blood in blood vessels (opposed to heart) |
| resistance is affected by what three things | viscosity, vessel length, vessel lumen size |
| Viscosity | resistance of fluid to its flow (thickness) |
| anemia | low red blood cell count means less thick so lower resistance |
| why does viscosity increase with dehydration | greater amount of red blood cells means thicker blood |
| increasing vessel length increases resistance why? | the longer the vessel the more resistance is going to be needed to oppose the blood flow |
| vessel radius | size of lumen (inside the arteries and veins) |
| smaller radius means | more resistance |
| larger radius | less resistance |
| Which has more resistance in terms of viscosity milkshake or water | milkshake because it is thinker, so it needs more resistance |
| Which has more resistance in terms of vessel length short vs long twisty straw | the long twisty straw because its going to take longer to transport liquid from point a to point b |
| which has more resistance in terms of vessel radius normal straw vs large milkshake straw vs small coffee stirrer | the coffee stirrer is going to have more resistance due to the small vessel radius |
| autonomic reflex's | regulate blood pressure short term (like going from sitting down to standing up) |
| Homeostatic systems | regulated by negative feedback loop, induces components of reflex arc |
| baroreceptors | response to vessel stretch sensory receptors located in aortic arch, carotid sinuses relay nerve signals along sensory neurons to the brain |
| cardiovascular center | in medulla, contains two autonomic nuclei: cardiac center and vasomotor center |
| cardiac center | influences blood pressure by influencing cardiac output (heart rate and force of contraction) |
| vasomotor center | influences blood pressure by influencing vessel diameter vasoconstriction / vasodilation influences resistance |
| Which center controls vasocontraction and vasodilation | Vasomotor center |
| vasoconstriction | when your blood vessels get tighter (constrict) |
| Vasodilation | when tour blood vessels grow or relax (dilation or restriction) |
| parasympathetic nervous system | "rest" and "digest" |
| sympathetic nervous system | "fight" or "flight" |
| sympathetic activation and adrenal secretion lead to | increased peripheral resistance Larger circulating blood volume Redistribution of blood flow |
| Increased peripheral resistance | more blood vessels are stimulated to constrict than to dilate; BP increases |
| Larger circulating blood volume | vasoconstriction of veins shifts blood from venous reservoirs: BP increases |
| Redistribution of blood flow | more blood to skeletal muscles and heart: less blood to most other structures |
| Steps of homeostatic system regulating blood pressure | 1. Sensory receptor Baroreceptors 2. Sensory neurons 3. Control Center: Cardiovascular center 4. Motor neurons 5. Effectors |
| Step 1: sensory receptor: Baroreceptors | detect change in stretch and alter sensory input |
| Step 2: Sensory neurons | signals are relayed along sensory neurons |
| Step 3: Control Center: cardiovascular Center | receives and responds to sensory input and alters motor input |
| Step 4: Motor Neurons | Signals are relayed along motor neurons |
| Step 5: Effectors | Blood vessels and Heart Respond |
| Blood pressure is influenced by | Blood volume |
| Volume is a Function of fluid intake and fluid output in what ways | Intake through drink and food Output through expired air, sweat, urine |
| Hormones can alter resistance, blood volume, or both True or false | True, they also participate in regulating blood pressure |
| Out of the was fluid can be outputted which way can be regulated | Urine because it's indirectly related to blood volume |
| what enzyme converts angiotensin one to angiotensin 2 | Angiotensin - converting enzyme (ACE) |
| what converts angiotensinogen to angiotensin 1 in the blood | Renin |
| Kidneys release what into blood in response to low BP or sympathetic nervous system activity | Renin |
| Where in the ACE enzyme located | in capillaries of the lung |
| Angiotensin 2 | raises blood pressure acts as a powerful vasoconstrictor stimulated thirst center acts of kidneys to decrease urine formation |
| what hormones cause kidneys to reduce urine output | Angiotensin II, aldosterone, ADH |
| what is the Antidiuretic hormone (ADH) | helps maintain or elevate blood pressure released from posterior pituitary release triggered by nerve signals from hypothalamus |
| What does ADH effect | increase water reabsorption in kidneys stimulates thirst center to increase fluid intake in large amounts it caused vasoconstriction |
| Aldosterone | helps maintain blood volume and pressure releases from adrenal cortex increases absorption of sodium ions and water in the kidneys (decreases urine output) |
| Atrial natriuretic peptide | decreases blood pressure released from atria of heart when walls are stretched stimulates vasodilation increases urine output |
| total blood flow increases during exercise to meet needs how | heart beats faster and stronger blood is removed from venous reservoirs blood is redistributed to the more active tissues |
| vessels lose elasticity with age and what does that effect | expand and recoil less readily makes it more difficult for heart to pump blood blood pressure may increase |
Created by:
Brooke_N